Curbs along paved roads and highways have openings for storm water to run off from the road into the storm drain or sewer and into a retention pond or into a river or stream. It is important to keep trash, debris, sand, oil and other pollutants out of the water entering the storm drain in order to prevent contamination of the rivers, lakes or streams during construction while the road is being repaired and when machinery or the like is being cleaned or serviced in the area. It is necessary to keep trash, sand and debris from going into the drain. To accomplish this, a temporary curb protecting device is put in place and removed when the service is complete. It therefore becomes desirable to have a temporary curb protector that can be rapidly installed and removed and which filters water or liquids passing through the curb opening into the storm drain. This filters the water passing into the curb opening at a lower portion of the curb opening and still allows some open area above the filter covering the curb opening to allow an overflow in the event of a heavy rain storm or rapid accumulation of water. The water can overflow the filter and go into the storm drain to prevent the street from flooding. Sometimes curb openings for storm drains are short and placement of a device is fairly simple but in the case of a long storm drain opening, such curb opening filters have a tendency to bend inward to allow accumulated debris and trash to pass under the filter. The present curb opening filter is designed to prevent this inward bend.